火中取宝,建水紫陶烧制有学问

火中取宝,建水紫陶烧制有学问插图
图:泰子作品

陶坯由软的、易碎的黏土变成坚硬的陶瓷这一烧制转变的过程由化学反应所控制,所有陶瓷概莫能外。其基本原理是当温度达到573℃左右时,陶坯晶体外的晶格结构被破坏,其中的结构水组成水分子从矿物中析出,同时陶坯中的硅土在体积上开始发生一系列的变化。温度逐渐上升,陶坯最终被烧制成熟。

The process of firing transformation of ceramic billet is controlled by chemical reaction. All ceramics are beyond the control of the whole process. The basic principle is that when the temperature reaches 573 ℃, the lattice structure outside the ceramic crystal is destroyed, and the water molecules of the structure water are separated from the minerals, and a series of changes have taken place in the volume of the silica in the ceramic billet. The temperature gradually increased, and the ceramic billet was finally burnt and mature.

由于不同的陶瓷种类在选料和工艺上存在差异,因此在这个基本的烧制原理之上,每种陶瓷的烧制有自己独特的地方,建水紫陶的烧制就有着自己的特色。

Due to the differences in material selection and process of different ceramic types, the firing of each kind of ceramic has its own unique features based on this basic firing principle, and the firing of Jianshui purple pottery has its own characteristics.

火中取宝,建水紫陶烧制有学问插图1

建水紫陶最终的成品是什么样,主要取决于烧成气氛。当窑内燃起熊熊烈火,窑膛中就会形成一个与外界截然不同的环境。

The final product of Jianshui purple pottery mainly depends on the firing atmosphere. When there is a big fire in the kiln, a completely different environment will be formed in the kiln.

建水紫陶泥料铁元素含量高,与氧接触反应生成氧化铁富含于陶坯之中;窑内处于燃烧状态,碳与氧反应生成氧化碳。这两种物质是基本固定的,因此影响烧成效果的一个主要变量就是烧制过程中对氧含量的控制。

The content of iron in Jianshui purple pottery mud is high, and the iron oxide is rich in the ceramic body; the kiln is in combustion state, and carbon reacts with oxygen to form carbon oxide. These two substances are basically fixed, so one of the main variables affecting the firing effect is the control of oxygen content in the firing process.

烧制过程中气闸开放,供氧充足,陶坯中的铁元素与氧充分结合,最终全部生成氧化铁,颜色呈红色,也就是氧化烧制后打磨出来的紫陶成品颜色。

During the process of firing, the airlock is open and oxygen is sufficient. The iron elements in the ceramic billet are fully combined with oxygen, and finally all iron oxide is produced. The color is red, that is, the finished color of purple pottery polished after oxidation and burning.

火中取宝,建水紫陶烧制有学问插图2

窑内温度升高的过程中逐渐关闭气闸,从而控制窑炉内的供氧量,还原气氛逐渐形成。强还原气氛时可以观察到火焰舔舐着窑炉口,那是火焰为了燃烧在攫取氧气。

When the temperature in the kiln increases, the air lock will be closed gradually, so as to control the oxygen supply in the kiln and the reduction atmosphere will be formed gradually. In the strong reducing atmosphere, it can be observed that the flame licks the kiln mouth, which is the flame grabbing oxygen for combustion.

这时,整个窑炉处于缺氧状态,氧化碳中的碳元素就会攫取氧化铁中的氧元素,帮助维持燃烧,从而将氧化铁剥离成为单质铁。整个还原反应完成后,紫陶成品表面附着一层单质铁,其颜色呈现黑灰色或黑紫色,也就是打磨出来后我们见到的黑紫色的紫陶作品。

At this time, the whole furnace is in anoxic state, and the carbon element in carbon oxide will grab the oxygen element in iron oxide to help maintain combustion, thus stripping iron oxide into elemental iron. After the whole reduction reaction is completed, a layer of simple iron is attached to the surface of the finished purple pottery, and the color is black gray or black purple, which is the black purple purple pottery works we see after grinding.

火中取宝,建水紫陶烧制有学问插图3

最后还想说一个问题,我们平时所说的建水紫陶收缩率大,其实是烧制过程中的两个阶段造成的:

Finally, I would like to say that the shrinkage rate of Jianshui purple pottery is high, which is caused by two stages in the firing process

一是温度上升到573℃左右时,陶坯中最后的晶体结构水被排出,陶坯变成真正不存在任何水的干坯,失去水使得建水紫陶第一次收缩。

The first is that when the temperature rises to about 573 ℃, the water in the final crystal structure of the ceramic body is discharged, and the ceramic body becomes a dry body without any water. The loss of water makes Jianshui purple pottery shrink for the first time.

二是建水紫陶泥料有多种成分构成,它们的熔点各不相同;建水紫陶的烧结温度超过1000℃,在如此高温之下,低熔点的物质熔化为液态填充进高熔点颗粒之间,陶坯收缩,陶坯密度加大,变得紧密结实。

Second, Jianshui purple pottery clay has a variety of components, their melting points are different; Jianshui purple pottery sintering temperature is more than 1000 ℃, under such a high temperature, the low melting point material melts into a liquid state and fills between the high melting point particles, the ceramic body shrinks, the density of ceramic body increases, and becomes compact and solid.

因此我们说建水紫陶“坚如铁”,其实就是达到最佳密度后,陶坯紧密结实;若达不到,则质地酥松、颜色生涩,甚至开裂变形,成为废品。因而,人称制陶是火中取宝的艺术。

Therefore, we say that Jianshui purple pottery is “as hard as iron”. In fact, when the optimum density is reached, the ceramic body will be compact and firm; if not, it will be loose in texture, dull in color, even cracked and deformed, and become waste. Therefore, it is called the art of taking treasure from fire.

另外,建水紫陶“声如磬”主要是针对还原烧制的作品而言。还原烧制使建水紫陶产生单质铁,因而敲击如磬音,氧化烧制的作品则没有这个效果。你可以选红色、黑色各一把壶,揭开壶盖,用手指弹击壶身,听听他们的区别。

In addition, the “sound like Qing” of Jianshui purple pottery is mainly for the works of reducing burning. The reduction firing makes the purple pottery produce simple iron, so it is knocked like a chime, and the work of oxidation burning has no effect. You can choose a pot in red and black, open the lid, hit the pot with your fingers and hear the difference.

未经允许不得转载:饮茶乎 » 火中取宝,建水紫陶烧制有学问

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